A coin with a transparent layer like bitcoin and a shielded layer that is private via zero knowledge proofs. There are controversies relating to the setup of this shielded system, ties to Israel, potential backdoor, past potential inflation bug and the project's current corporate development.

I would look into these controversies and the arguments for and against them if you're interested in the project.

Zero knowledge proofs but with the 21million cap. Kinda like an in-between of monero and Bitcoin. It's not private by default.

I decided to buy about a hundred dollars almost exactly a year ago just to test it out and see if it was useful, I wasn't that impressed tbf but at least it got a fun little return for me that I can throw back in btc/xmr.

In general though I would typically reccomend for most usecoses that might call for something like zec just using btc privacy tools if possible instead coinjoin/silent payments etc. and if that level of anonymity isn't sufficient then I would just recommend using xmr at that point. But maybe there is some weird/specific use case I'm not yet aware of.